Router and Switch VLAN routing

[keith.burke]

Hello,

I have a CISCO 4331 with a 24 Port Switch Module installed internal to the router.  I also have a Cisco 9300 24-port SFP switch (no network module).  I am trying to establish connectivity between all three devices.  Normally, I set up VLAN Interfaces on both the 4331 and the installed switch module.  No issues, easy peasy.  Now that I am introducing the 9300, I want to set up a VLAN interface on that as well and establish connectivity across all three devices while maintaining routable IP addresses within the VLAN 2 network space assigned to me.  Pretty easy to do, I set up my VLAN interfaces, assign IP's, set the ports to Trunk, and boom...connectivity.  I've tested and succeeded in being able to establish connectivity and ping across all three devices. Is there a way, using G0/0/1 on the Router, to connect the 9300 and have all three devices have IP and connectivity WITHOUT trunking between the two switches directly and keeping all three devices within the same IP space and subnet. I have been unsuccessful with everything I have tried to do so far.  I've set up sub-interfaces on Gi0/0/1, assigned it an IP, and established connectivity to the 9300, but I lose connectivity to the internal switch.  If I remove the sub-interface and IP on Gi0/0/1 and set up my VLAN interface, I regain connectivity to the internal switch, but lose connectivity to the 9300.

I am using VLAN 2 for my VLAN

Let's use the 10.95.14.160 /29 for the network

RTR: Assigned IP - 10.95.14.161 /29

Internal Switch : Assigned IP - 10.95.14.162 /29

External Switch: Assigned IP - 10.95.14.163 /29

I appreciate any help and assistance.  This should be easy, but I'm running in circles

[balaji.bandi]

As per my understanding :

Router

RTR: Assigned IP - 10.95.14.161 /29

router with switch Module -

Internal Switch : Assigned IP - 10.95.14.162 /29

Cat 9300

External Switch: Assigned IP - 10.95.14.163 /29

May be not clear to be why you want another IP address to router, Since the IP allocated already  part of the router right ?

or am i miss understand the requirement ?

[keith.burke]

BB,

Thank you for the reply.  I would say that I explained it wrong and not that you misunderstood.

In summary, I have all three devices with the IP's above that need to communicate and route VLAN 2 with the given IP's across all three devices, without creating a trunk from switch to switch. I'd like to connect the 9300 directly to the router using Gi 0/0/1.  Unfortunately when I do this, I can not communicate between all three devices. I can communicate between the router and the 9300, but lose connectivity to the internal switch.  There is also no connectivity between the 9300 and internal switch when utilizing Gi 0/0/1.   

Thanks again for your reply and assistance,

Keith

[balaji.bandi]

internal switch  - is layer 2 right, this is controlled by Layer in the router?

to understand remove sensitive information post running-config of the router

show run

show module

same with Cat 9300

Do you have any small diagram how your exiting connection working, ?

[keith.burke]

BB,

Here are the running configs for the 4331 and the Internal Switch as they currently work.  The communicate with Interface VLAN 2 configured on each device.  Currently, the 9300 is not connected to the router or the switch.  My goal is to connect the 9300 with interface  G 0/0/2 on the 4331 and assign a Vlan 2 interface on the 9300 so all three devices can communicate and route to each other.

Like I said, normally I would just connect switch to switch with a trunk port, but I am restricted in doing that on the install currently as I do not have the equipment on hand to do so (a media converter as the internal switch is Ethernet and the 9300 is SFP).

Please note that in the attached diagram, there is no Network Module present in the 9300.

[Georg Pauwen]

Hello,

just a thought: you could try to configure a BDI on the router, and connect both the internal switch module as well as the subinterface connected to the 9300 switch to that BDI. The config could look something like below (not sure if I got the syntax right):

4331

interface GigabitEthernet0/0/1.2

description Link to 9300
encapsulation dot1q 2
service instance 2 ethernet
bridge-domain 2
!
interface Ethernet-Internal1/0/0
description Backplane to SW-Module G0/26
service instance 2 ethernet
encapsulation untagged
bridge-domain 2
!
interface BDI 2
mtu 9216
ip address 10.95.14.161 255.255.255.248

Switch Module

interface GigabitEthernet0/26
switchport trunk encapsulation dot1q
switchport trunk vlan allowed 2
switchport mode trunk
!
interface Vlan2
ip address 10.95.14.162 255.255.255.248
no ip redirects
no ip proxy-arp
!
ip route 0.0.0.0 0.0.0.0 10.95.14.161

[keith.burke]

Georg,

Thank you for the assistance.  It appears that on my 4331, I can not issue the service instance command on the sub-interface.  But I am trying to research some more.  Thank you again for the assistance and any other help you might provide.

Keith

[balaji.bandi · Accepted solution]

Hope below document help you based on the information :  ( not sure what License you have check the License requirement also)

https://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/200650-Understanding-Bridge-Virtual-Interface.html

[keith.burke]

Thanks for the link, it definitely explained things well.  Unfortunately I was unable to establish the connectivity between the two switches and the router.  The BDI2 I created kept showing as DOWN/DOWN and I wasn't able to configure the internal interfaces to the internal switch with the BDI commands.  Something about those internal interfaces.  I'll keep plugging away at it and if I figure it out, I'll be sure to post here.  Thank you all for the assistance.